Composite roofing overlay containing recycled paint waste and recycled crushed glass

ABSTRACT

A composite roofing overlay containing paint waste is provided for use on a roof surface. The composite roofing overlay includes a bedding cement containing water-based paint waste and crushed recycled glass, a porous fabric embedded in the bedding cement, and at least one primer coat over the porous fabric and bedding cement. The composite roofing overlay may be used in combination with an overlying waterproof roofing membrane to provide an effective waterproof seal to new or existing roof structures.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. application Ser. No.13/221,988 filed Aug. 31, 2011, now U.S. Pat. No. 8,334,361, which is adivision of U.S. Pat. application Ser. No. 11/753,605, filed May 25,2007, now U.S. Pat. No. 8,029,868, which claims the benefit of U.S.Provisional Application No. 60/808,894, filed May 26, 2006. Thisapplication also claims the benefit of U.S. application Ser. No.13/370,371 filed Feb. 10, 2012, which is a continuation-in-part ofapplication Ser. No. 13/221,988 (U.S. Pat. No. 8,334,361). The entirecontents of said applications are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a composite roofing overlay containingrecycled paint waste and recycled crushed glass, and more particularly,to a composite roofing overlay for use on new or existing roof surfaces.

Low-sloped roof construction is used for a wide variety of commercialand industrial buildings. Typically, low-sloped roofs include awaterproof layer or membrane which prevents the penetration of waterresulting from precipitation or condensation on the roof surface. Wherethe waterproof layer comprises a membrane, the membrane may be comprisedof materials such as EPDM rubber, thermoplastic polyolefins (TPO),polyvinyl chloride (PVC), chlorosulfonated polyethylene, and modifiedbitumen. The waterproof layer may also comprise a composite includinglayers of hot applied asphalt, reinforcing fiberglass, cloth, or paper.Elastomeric sealers may also be used in combination with cloth to form awater-resistant membrane. A number of additional layers may be includedbelow the membrane such as insulation, supporting cover boards, andvarious vapor or thermal barrier layers.

Re-roofing an existing low-sloped roof is an expensive process as ittypically requires tearing off the existing roof. In addition, there isa period of time during the re-roofing process in which the insidestructure is exposed to outside weather elements, rendering the insidestructure vulnerable to water damage. Further, tearing off an existingroof structure is environmentally undesirable as most of the componentsare discarded in a landfill, and the underlying components, such asinsulation, also have to be replaced. Accordingly, it would be desirableto restore the existing roof.

In order to avoid the expense of removing and replacing an entire roof,an increasing emphasis has been placed on applying a secondary roofingsystem over an aged roof which allows all of the sub-roof layers to beutilized. Currently, the application of an EPDM or TPO membrane iswidely used in re-roofing processes. In conjunction with the applicationof such a membrane, the underlying substrate which supports the membraneis important. Typical support substrates which have been used belowroofing membranes include cover boards such as iso-board, asphalticboard, mineral fiberboard, fiberglass board, plywood or oriented strandboard (OSB), wood fiberboard, or mineral aggregate board. While thesematerials generally lie flat in new construction, when used in reroofingapplications, they may cause improper sloping, blisters, bubbling,raising, or seam separation due to the multiple underlying layers. Inaddition, support substrates comprised of these materials are notgenerally waterproof, and therefore not capable of preventing waterinfiltration into the roofing system in the event that the roof coverbecomes compromised.

It would be desirable to provide an improved support for a roofingmembrane which does not suffer from the drawbacks of roofing substratessuch as cover boards.

Accordingly, there is a need in the art for a substrate which may beused in conjunction with a roofing membrane for use in new roofingconstruction or on an existing roof which is cost-effective,environmentally friendly, and which provides effective sealing andadhesion characteristics.

SUMMARY OF THE INVENTION

Embodiments of the invention meet that need by providing a compositeroofing overlay produced using recycled paint waste and recycled crushedglass which provides a waterproof barrier on a roof surface. Thecomposite roofing overlay can be used in combination with an overlyingroofing membrane such as an ethylene propylene diene monomer (EPDM) or athermoplastic polyolefin (TPO). Alternatively, an elastomeric sealantmay be applied over the composite roofing overlay to form a combinationroofing overlay/membrane.

While the composite roofing overlay described herein is primarily foruse with existing roofs, it may also be used in new roof construction.The composite roofing overlay is also relatively inexpensive andenvironmentally friendly as it contains recycled paint waste andrecycled crushed glass, and eliminates the need to dispose of oldroofing materials in a landfill. In addition, the roofing overlay ismonolithic and waterproof, which offers construction flexibility beforethe final roof cover is installed.

According to one aspect of the invention, a composite roofing overlay isprovided which comprises bedding cement comprising water-based paintwaste and recycled crushed glass; a porous fabric embedded in thebedding cement; and at least one primer coat over the porous fabric andbedding cement. By “water-based paint waste”, it is meant water-basedpaint such as latex paint which has been collected after various paintjobs, paint which is past its shelf life, paint from municipalcollection facilities, or any other unused latex paint used alone or incombination with paint waste. By “porous fabric,” it is meant a fabrichaving a sufficient porosity to allow the bedding cement and/or primerto wick the fabric.

The bedding cement preferably comprises from about 10 to about 50% byweight water-based paint waste and from about 40 to 80% by weightcrushed recycled glass. The recycled crushed glass preferably has aparticle size of from about 0.001 mm to about 1.0 mm. The porous fabricpreferably comprises a polyester cloth.

In one embodiment, the composite roofing overlay further includes anelastomeric sealer over the primer coat. The elastomeric sealer maycomprise a paint waste residue comprising treated oil-based paint waste,water-based paint waste, at least one emulsifier, a virgin latexpolymer, and a plasticizer. By “oil-based paint waste,” it is meantoil-based paint collected as described above which includes solvents. By“virgin latex polymer,” it is meant a polymer which is used in the formin which it was manufactured in an uncompounded state, i.e., it has notbeen formed into a product or mixed with any recycled polymer.

In one embodiment, the composite roofing overlay exhibits a compressivestrength of about 1000 psi and a tensile strength of about 100 psi.

In another embodiment of the invention, a combination waterproof roofingmembrane overlying a composite roofing overlay is provided, where thecomposite roofing overlay comprises bedding cement comprisingwater-based paint waste and recycled crushed glass, a porous fabricembedded in the bedding cement, and at least one primer coat over theporous fabric and bedding cement.

In one embodiment, the waterproof roofing membrane is selected fromEPDM, thermoplastic polyolefin (TPO), polyvinyl chloride, modifiedbitumen, and chlorosulfonated polyethylene membranes. In thisembodiment, the waterproof roofing membrane is preferably adhered to thecomposite roofing overlay with an adhesive which has been applied in apredetermined pattern.

In another embodiment, the waterproof membrane comprises an elastomericsealer applied to the surface of the composite roofing overlay, whichforms a waterproof membrane. The elastomeric sealer may comprise a paintwaste residue comprising treated oil-based paint waste, water-basedpaint waste, at least one emulsifier, a virgin latex polymer, and aplasticizer.

Accordingly, it is a feature of embodiments of the invention to providea composite roofing overlay or a combination waterproof roofingmembrane/composite roofing overlay which provides an effectivewaterproof seal to a roof. These, and other features and advantages willbecome apparent from the following detailed description, theaccompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a composite roofing overlay andwaterproof roofing membrane in accordance with an embodiment of theinvention; and

FIG. 2 is a cross-sectional view of a composite roofing overlayincluding an elastomeric sealer/membrane in accordance with anotherembodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the invention provide a high-performance compositeroofing overlay which bonds to an existing roof cover and effectivelyseals isolated areas or an entire roof surface, forming a waterproof,seamless monolithic support and leveling layer. Such composite roofingoverlays can be used on an existing roof to extend the life of the roof.Alternatively, the composite roofing overlay may be used to fabricate anew roof. The composite roof overlay is waterproof and may be used incombination with a waterproof roofing membrane to provide a durable,double-layered waterproof barrier.

While the composite roof overlay is primarily designed to be used onflat or low-sloped roofs, it may be used in any type of roofingapplication as a support for an outer roofing membrane. The overlay maybe used on all types of flat or low-sloped roofs including metal,gravel, smooth buildup, membrane, and metal roofs. The overlay may alsobe applied to aged sprayed polyurethane foam covered roofs. It may alsobe used in vegetative green roofs and other kinds of applications inwhich it is desired to provide waterproof properties, such as ponds.

The use of the composite roofing overlay is environmentally desirable asit comprises recycled paint and crushed recycled glass as majorcomponents, i.e., the overlay is formed from bedding cement whichcomprises at least 25% by weight recycled water-based paint waste, andpreferably at least 50% by weight (after drying), and preferably atleast 50% by weight recycled crushed glass. Thus, the recycled contentof the composite roofing overlay is essentially 100%, making the overlayrelatively inexpensive to manufacture.

The water-based paint materials used to produce the bedding cement maybe obtained from several sources including, but not limited to,automotive companies, industrial OEM equipment manufacturers,architectural painting contractors, household paint waste, paintmanufacturers (who dispose of off-spec materials and waste products),paint distributors which have accumulated paint which is past its shelflife, paint contractors who accumulate paint residues left over fromvarious paint jobs, and local land fills that accept paint waste fromconsumers.

The water-based paint waste (latex paint waste) may be used in the formin which it is collected. However, the paint waste is preferablyscreened prior to use to ensure that it is free of large particles orother foreign matter, followed by blending and/or conditioning. Forexample, a macerator pump may be used to homogenize the pre-screenedlatex by grinding down larger waste agglomerates into smaller particlesizes. After screening, blending and/or conditioning, the water-basedpaint preferably has a viscosity of between about 1,000 to 3,000 cps anda solids content of about 40% to 60%.

The bedding cement preferably comprises about 25% by weight water-basedpaint waste and about 75% by weight crushed recycled glass. A preferredsource for the recycled glass is Horry County Solid Waste Authority,Conway, S.C. The crushed glass preferably has a particle size of fromabout 0.001 mm to 1.0 mm. It has been found that the use of crushedglass in the bedding cement provides a less expensive alternative to theuse of other materials such as sand and provides the desired propertieswhen combined with paint waste in the bedding cement.

The bedding cement is non-elastic, crack-resistant, and forms a strongbond with underlying roof substrates such as single-ply roofingmembranes, modified bitumen, metal roofs, and sprayed polyurethane foam.Unlike traditional lime-based cements, the bedding cement is in the formof a flowable, heavy liquid which does not require preparation or mixingprior to use. The bedding cement also exhibits a long working time priorto curing, i.e., the curing time is controlled by water evaporationrather than chemical reaction, and is much slower, requiring days tocure vs. hours for a chemical system. This provides an advantage overquickly curing chemical systems, which require final completion of theroof surface before curing occurs, and which could result in anincomplete or imperfect surface in situations where production orweather delays occur.

The bedding cement may optionally include from about 1 to about 10% byweight of a plasticizer such as butyl benzyl phthalate. The plasticizerfunctions as a thixotrope, and may be included in applications where thebedding cement is used as a non-slump bedding cement, i.e., where thecement does not level upon application. This bedding cement compositionmay be used in situations where a desired slope needs to be maintained,e.g., to maintain proper drainage.

In one method of forming the composite roofing overlay, the beddingcement is applied to a roofing surface in liquid form containing about80% by weight solids and water. The bedding cement may be pumped ortrawled onto the roofing surface. After application of the beddingcement, a porous fabric is embedded in the bedding cement. One suitableporous fabric is a spun polyester cloth available from InternationalCoatings under the designation Polylace. Another suitable fabric isSpunflex®, commercially available from Conklin. The roofing fabric maybe applied in the form of a roll which is cut to proper length.

When the bedding cement/porous fabric combination has dried (withinabout one week under dry weather conditions), at least one coating ofsurface primer (about 1 gallon per 100 square feet) is applied to theentire surface. It should be appreciated that because of the porousnature of the fabric, the primer applied over the fabric not onlysaturates the fabric and forms a film over the fabric, but alsopenetrates and adheres to the bedding cement. The primer may optionallyalso be applied to the surface of the bedding cement prior toapplication of the polyester cloth, followed by another application ofprimer after the fabric is applied.

The primer may comprise any commercially available primers such as thoseavailable from Sealoflex Waterproofing Systems and Hydro-Stop Roofingand Waterproofing Systems. Alternatively, the primer may compriseoil-based paint waste and water-based paint waste as described in U.S.Pat. No. 8,029,868, which is incorporated herein by reference. Such aprimer comprises about 24% by weight of paint waste residue formed fromoil-based paint waste, about 57% by weight water-based paint waste,about 4% of an emulsifier; and about 2% by weight of a plasticizer. Theoil-based paint waste may be obtained from the same sources describedabove, and is preferably treated by removal of a portion of the solventsin the paint waste under vacuum at a temperature of about 225° F. suchthat a paint waste residue is formed. The paint waste residue is thenemulsified by the addition of one or more surfactants as described inU.S. Pat. No. 8,029,868.

If desired, an additional coating such as an elastomeric caulk may alsooptionally be included on the primer layer of the bedding cement asdescribed in U.S. Pat. No. 8,029,868. The elastomeric caulk can be usedto correct imperfections on the dried composite overlay surface.

The resulting composite roofing overlay provides a monolithic waterbarrier that bonds continuously to an existing roof with no seams.Because the composite roofing overlay provides a waterproof barrier,there is no need for additional waterproofing or adhesion promotinglayers which are normally required with the use of roof cover board.Installation of the composite roofing overlay is simple as it requiresno cutting and fitting, no handling of cover boards, no fasteners, andshorter labor time. The bedding cement has good leveling uponapplication, even with sunken and uneven roof areas. It should beappreciated that larger depressions can be pre-filled with the beddingcement before the final application of the overlay.

The composite roofing overlay forms a waterproof surface soon afterapplication, and after a preferred drying time of about one week atambient temperatures, exhibits a compressive strength (50×50×50 mm) ofabout 900 psi (ASTM D 1621), a flexural strength (40×40×160 mm) of about200 psi (ASTM C 348), and a tensile strength (t/D=0.25) of about 100 psi(ASTM D 3967).

When used on an existing built-up roof, the composite overlay thicknessis preferably about ¼ inch to ½ inch (0.64 to 1.28 cm).

In one preferred embodiment, a waterproof roofing membrane is appliedover the composite roofing overlay. Preferred waterproof membranes aresingle-ply elastomeric membranes which include EPDM, TPO, polyvinylchloride, modified bitumen, and chlorosulfonated polyethylene membranes.Suitable membranes are commercially available from Firestone, Carlisle,and GAF. However, it should be appreciated that any pre-cured roofingmembrane may be used in conjunction with the composite roofing overlay.It should also be appreciated that the composite roofing overlay may beused as a seamless waterproof underlayment for use in flat roofapplications or in any applications where cover board is typically used.

As an alternative to the use of a separate waterproof membrane, anelastomeric sealer may be applied directly over the composite roofingoverlay. Upon drying, the elastomeric sealer forms a waterproofmembrane, which eliminates the need for a separate roofing membrane asdescribed above. One example of an elastomeric sealer compositioncomprises paint waste residue formed from treated oil-based paint waste,water-based paint waste, at least one emulsifier, a virgin latexpolymer, and a plasticizer. The elastomeric sealer preferably comprisesabout 24% by weight of the paint waste residue formed from treatedoil-based paint waste, about 20% water-based paint, about 4% of anemulsifier, about 37% of a virgin latex polymer, and about 2% by weightplasticizer as described in U.S. Pat. No. 8,029,868, incorporated hereinby reference. Other commercially available elastomeric sealers which aresuitable for use include Sealoflex® CT Top and Hydro-Stop FM4470.

The elastomeric sealer may be formed by providing the formed paint wasteresidue and then phase-inverting the paint waste residue to anoil-in-water emulsion by slowly adding surfactants and warm water priorto the addition of the water-based paint waste and other components.

Referring now to FIG. 1, a composite roofing overlay structure 10 formedon a roofing surface 12 is shown. Bedding cement 14 is applied to theroof surface 12 which is preferably cleared of gravel and/or soil. Thebedding cement may be applied in an amount of about 30 gallons per 100square feet for a gravel-cleared, gravel covered built-up roof, andabout 20 gallons per square feet for either a smooth, built-up roof, asingle-ply membrane, a shingle surface, or new roof substrate.

A layer of porous fabric 16 is embedded in the wet bedding cement. Ininstances where the roof contains depressed areas, the beddingcement/porous fabric combination can be applied in successive layers tothose areas after each of the previously layers is sufficiently dry. Insuch instances, the bedding cement may be applied without fabric. Itshould be appreciated that the drying time will vary depending on thethickness of the applied layer(s) and the weather conditions. The layersare considered to be dry when they do not deform upon applied pressureand/or can be walked on without deformation.

When the bedding cement/porous fabric combination is dry (can be walkedon without deformation), at least one coating of surface primer 18 isapplied at about 1 gallon per 100 square feet to the entire surface toform the composite roofing overlay 10. A separate waterproof roofingmembrane 20 may then optionally be applied over the composite roofingoverlay as shown. The waterproof membrane is preferably adhered to thecomposite roofing overlay using an adhesive. In one embodiment, themembrane may be fully adhered to the roof substrate. The adhesive ispreferably a polyurethane-based adhesive and may include commerciallyavailable water or solvent based adhesives and contact cements.

Alternatively, the membrane may be fastened with the use of acommercially available single-part moisture-cured urethane sealant.Examples of such sealants are Titebond® from Franklin International orNP1™ from Sonneborn. In this embodiment, the urethane sealant ispreferably applied in a criss-cross pattern of linear beads with seamspacing of about four feet, where the membrane overlap seam is coatedwith bonding adhesive. Where excessive wind lift is a concern, the seamspacing may be reduced to two feet. In addition, the membrane overlapseams may be covered with a six-inch wide strip of a three-ply membraneconsisting of elastomeric sealer/cloth/elastomeric sealer.

Referring now to FIG. 2, an alternative embodiment is shown in which anelastomeric sealer 22 is applied to the composite roofing overlay. Uponapplication to the composite roofing overlay, a film is formed whichforms a membrane which is bonded directly to the bedding cement. Thecombination of the composite roofing overlay and elastomeric sealer/filmforms the waterproof roof cover.

Having described the invention in detail and by reference to preferredembodiments thereof, it will be apparent that modifications andvariations are possible without departing from the scope of theinvention.

What is claimed is:
 1. A composite roofing overlay comprising: beddingcement comprising water-based paint waste and crushed recycled glass; aporous fabric embedded in said bedding cement; and at least one primercoat over said porous fabric and bedding cement.
 2. The compositeroofing overlay of claim 1 further including an elastomeric sealer oversaid at least one primer coat.
 3. The composite roofing overlay of claim2 wherein said elastomeric sealer comprises a paint waste residuecomprising treated oil-based paint waste, water-based paint waste, atleast one emulsifier, a virgin latex polymer, and a plasticizer.
 4. Thecomposite roofing overlay of claim 1 wherein said porous fabriccomprises a polyester cloth.
 5. The composite roofing overlay of claim 1wherein said bedding cement comprises from about 10 to about 50% byweight water-based paint waste and from about 40 to 80% by weightcrushed recycled glass.
 6. The composite roofing overlay of claim 1wherein said crushed recycled glass has a particle size of from about0.001 mm to 1.0 mm.
 7. The composite roofing overlay of claim 1 having acompressive strength of about 1000 psi.
 8. The composite roofing overlayof claim 1 having a tensile strength of about 100 psi.
 9. Incombination, a waterproof roofing membrane overlying a composite roofingoverlay, said composite roofing overlay comprising bedding cementcomprising water-based paint waste and recycled crushed glass; a porousfabric embedded in said bedding cement; and at least one primer coatover said porous fabric and bedding cement.
 10. The combination of claim9 wherein said waterproof membrane is selected from EPDM, thermoplasticpolyolefin (TPO), polyvinyl chloride, modified bitumen, andchlorosulfonated polyethylene membranes.
 11. The combination of claim 9further comprising an elastomeric sealer applied to the surface of saidcomposite roofing overlay.
 12. The composite roofing overlay of claim 11wherein said elastomeric sealer comprises a paint waste residuecomprising treated oil-based paint waste, water based paint waste, atleast one emulsifier, a virgin latex polymer, and a plasticizer.
 13. Thecombination of claim 9 wherein said bedding cement comprises from about10 to about 50% by weight water-based paint waste and from about 40 to80% by weight recycled crushed glass.
 14. The combination of claim 9wherein said waterproof roofing membrane is adhered to said compositeroofing overlay with a polyurethane sealant.
 15. The combination ofclaim 14 wherein said polyurethane sealant has been applied in acriss-cross pattern.